BADR UNIVERSITY IN CAIRO
جامعةبـــدربالقــامرة  Badr University, Cairo

Dissolution is the process by which a solid solute enters into a solution when added to a suitable solvent

Dissolution rate: the rate at which the solid dissolves in a solvent.

The above diagram shows the steps of disintegration, dissolution and absorption of solid drug form tablet or capsule.

The dissolution of a solid drug is the slowest step; hence it is the rate limiting step (RLS) in absorption of such drugs.

The dissolution of solids in a liquid is of two stages
1- An interfacial reaction liberation of solute molecules from the solid phase. The solution in contact with the solid will be saturated.

2- Migration of solute molecules through the boundary layers surrounding the crystal to the bulk of the solution via diffusion or convection, which determine the rate of dissolution.